I cannot for the life of me figure out why blend space inside persona will not show the parameters. Any ideas?
This isn’t an answer, but I’m having exactly the same problem. If I get an answer I’ll leave it here, I’ll be watching your question as well, if you figure it out please let me know 
So, found out that this blend space is specific to 4.15 and it’s a new interface.
4.15 Preview Release | Feature Highlight | Unreal Engine - YouTube tune into 43:20
Documentation said to be released with the finished version.
They also said, which I found helpful, is that you shouldn’t use previews to build your final product because features may change and not be compatible in the final release.
I found an answer for preview.
Shift Key + MouseMove
On the left side you have to click on ‘Asset details’ tab and you’ll have the parameters in the ‘Axis Settings’ section. It took me a while to find that as well.
It works in 4.16 at least.
Thnx works now